Effect of Glucagon on Serum LH

Abstract

IntroduetionGlucagon, besides its known metabolie actions, has shown interesting stimulatory effects on several polypeptide hormones such as insulin (Samols, Marri and Marks 1966), growth hormone (Mitchel/, Byrne, Sanchez and Sawin 1970, Wieland, HaI/-berg and Zorn 1973, Spathis, Bloom, Jeffcoate, Mil/er, Kurtz, Pyassena, Smith and Naba"o 1974 and ACTH (Spathis, Bloom, Jeffcoate, Mil/er, Kurtz, Pyassena, Smith and Naba"o 1974).No effect was found on the luteinizing hormone (LH) when glucagon was administered intravenously (Eddy, Jones and Hirsch 1970).The method of administration of glucagon is very important. When given intravenously many workers did not observe a stimulation of the several hormones mentioned (Danforth and Rosenfeld 1970, Jones andHirsch 1970), while administration of glucagon subcutaneously or even better, intramuscularly, produced a very good stimulation (Gi/boa, R osen berg, Hertzeanu, Langstein 1973, Wanderschueren, Lodeweyckx, Wolter, Malvaux, Eggermont and Eckeis 1974).We therefore investigated the effect of glucagon on plasma LH after intramuscular administration. Material and MethodsGlucagon 0.03 mg/kg body weight was administered to 13 healthy subjects, males and females. In one separate patient the glucagon stimulation was done after a test with LHRH showed good LH reserve. The level of plasma LH was estimated after intramuscular injection of normal saline in 2 subjects, as controls. Blood was taken at 0, 1, 2 and 3 hours after the injection, plasma was immediately separated and frozen until examined. LH was estimated by RIA ("Sorin" kit) and the results expressed in milliunits/ml (2nd IRP). Table 1. Plasma LH (mu/ml) in 11 subjects stimulated with glucagon 0.03 mg/kg i.m. and in 2 control subjects, after saline injection Results and Comments

Signal Transduction Mechanisms for Glucagon-Induced Somatolactin Secretion and Gene Expression in Nile Tilapia (Oreochromis niloticus) Pituitary Cells

“…Second, a positive correlation between circulating levels of GCG and GH ( 21 ) and administration of GCG induces GH secretion in mammals ( 22 – 24 ). Finally, GCG directly induces the luteinizing hormone (LH) ( 25 ) and corticotropin secretion ( 26 ) in humans. These findings trigger the possibility that GCG can act on multiple pituitary cell types.…”